diff --git a/src/engine/fileOpsIns.cpp b/src/engine/fileOpsIns.cpp
index ddf9a1df7..602fbba55 100644
--- a/src/engine/fileOpsIns.cpp
+++ b/src/engine/fileOpsIns.cpp
@@ -650,12 +650,12 @@ void DivEngine::loadY12(SafeReader& reader, std::vector<DivInstrument*>& ret, St
     ins->fm.ops = 4;
     ins->name = stripPath;
 
-    for (int i = 0; i < 4; ++i) {
+    for (int i : {0,1,2,3}) {
       DivInstrumentFM::Operator& insOp = ins->fm.op[i];
       uint8_t tmp = reader.readC();
       insOp.mult = (tmp & 0xF);
       insOp.dt = ((tmp >> 4) & 0x7);
-      insOp.tl = (reader.readC() & 0xF);
+      insOp.tl = (reader.readC() & 0x3F);
       tmp = reader.readC();
       insOp.rs = ((tmp >> 6) & 0x3);
       insOp.ar = (tmp & 0x1F);
@@ -671,7 +671,7 @@ void DivEngine::loadY12(SafeReader& reader, std::vector<DivInstrument*>& ret, St
     }
     ins->fm.alg = reader.readC();
     ins->fm.fb = reader.readC();
-    reader.seek(14, SEEK_CUR);
+    reader.seek(62, SEEK_CUR);
     ret.push_back(ins);
   } catch (EndOfFileException& e) {
     lastError = "premature end of file";
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index d3218b30c..47b81f6eb 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -1290,9 +1290,9 @@ void FurnaceGUI::openFileDialog(FurnaceGUIFileDialogs type) {
       if (!dirExists(workingDirIns)) workingDirIns=getHomeDir();
       hasOpened=fileDialog->openLoad(
         "Load Instrument",
-        {"compatible files", "*.fui *.dmp *.tfi *.vgi *.s3i *.sbi *.bnk *.ff *.opm",
+        {"compatible files", "*.fui *.dmp *.tfi *.vgi *.s3i *.sbi *.y12 *.bnk *.ff *.opm",
          "all files", ".*"},
-        "compatible files{.fui,.dmp,.tfi,.vgi,.s3i,.sbi,.bnk,.ff,.opm},.*",
+        "compatible files{.fui,.dmp,.tfi,.vgi,.s3i,.sbi,.y12,.bnk,.ff,.opm},.*",
         workingDirIns,
         dpiScale
       );
diff --git a/src/gui/settings.cpp b/src/gui/settings.cpp
index f1565b8ee..5ed9cf0ad 100644
--- a/src/gui/settings.cpp
+++ b/src/gui/settings.cpp
@@ -2485,6 +2485,7 @@ void FurnaceGUI::applyUISettings(bool updateFonts) {
   ImGuiFileDialog::Instance()->SetFileStyle(IGFD_FileStyleByExtension,".vgi",uiColors[GUI_COLOR_FILE_INSTR],ICON_FA_FILE);
   ImGuiFileDialog::Instance()->SetFileStyle(IGFD_FileStyleByExtension,".s3i",uiColors[GUI_COLOR_FILE_INSTR],ICON_FA_FILE);
   ImGuiFileDialog::Instance()->SetFileStyle(IGFD_FileStyleByExtension,".sbi",uiColors[GUI_COLOR_FILE_INSTR],ICON_FA_FILE);
+  ImGuiFileDialog::Instance()->SetFileStyle(IGFD_FileStyleByExtension,".y12",uiColors[GUI_COLOR_FILE_INSTR],ICON_FA_FILE);
   ImGuiFileDialog::Instance()->SetFileStyle(IGFD_FileStyleByExtension,".bnk",uiColors[GUI_COLOR_FILE_INSTR],ICON_FA_FILE);
   ImGuiFileDialog::Instance()->SetFileStyle(IGFD_FileStyleByExtension,".fti",uiColors[GUI_COLOR_FILE_INSTR],ICON_FA_FILE);
   ImGuiFileDialog::Instance()->SetFileStyle(IGFD_FileStyleByExtension,".bti",uiColors[GUI_COLOR_FILE_INSTR],ICON_FA_FILE);